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United States Patent NIETHOD OF COATING AND DRAWING METAL ANDCOMPOSITION THEREFOR John A. Henricks, Lakewood, Ohio No Drawing.Original No. 2,588,234, dated March 4,

1952, Serial No. 193,290, October 31, 1950. Application for reissueMarch 1, 1954, Serial No. 413,490

ZlClaims. (Cl. 148-615) This application is a continuation-in-part of mycopending application Serial No. 665,905 filed April 29, 1946, nowabandoned. The invention relates to the lubrication of sliding metalsurfaces. In particular, it relates to the treatment and lubrication ofsurfaces under conditions of extreme pressure and surface temperature asencountered in'the drawing and deforming of metalssuch as steel.

Ordinary lubricating oils fail to give satisfactory performancecharacteristics in the drawing and deforming of harder metals such assteel with the result that tearing of the metal or galling of the diesfrequently occurs. Even extreme pressure lubricating oils areunsatisfactory for this purpose and are not recommended. The acceptedtheory is that the failure of such lubricants is due to a squeezing-outof the lubricants from between the work and die because of the extremepressure used. Accord ingly, to counteract this extreme pressure and toprevent the squeezingout of lubricants, it has been the general practiceto utilize as drawing compositions lubricants contaiiiing infusiblepigments such as clay, lime, mica, calcium or magnesium carbonates,titanium dioxide and graphite. The function of such pigment isto'separate-the die and the workpiece at points of extreme deformationand intimate contact when the pressure or temperature is too great to bewithstood by the organic constituents of the lubricating material. Whilesuch compositions do function better than the prior non-pigmentedmaterials, an examination of the work drawn with the aid of such drawingcompositions discloses minute particles of pigments embedded therein anda surface with an undesirable dull finish.

An additional objection to infusible pigment fillers is their abrasiveor lapping action which increases friction and oil temperatures duringthe drawing operation.

It has been established (Bowden and Ridler in Proceedings of the RoyalSociety 154,640; 1936) that in sliding friction between dry metallicsurfaces the frictional junction reaches and maintains the melting pointof thelower melting metal. This readily explains the galling of dies andthe welding and seizure of'moving parts. From this it can be seen thatthe failure of a drawing lubricant may well be caused by hightemperature destruction or carbonization of the lubricant with theresultant galling and seizure instead of pressure squeezingout thematerial from the working surfaces as previously believed.

From this it follows that for the most satisfactory drawing and workingof metal, effective lubrication throughout the entire temperature rangebelow the melting point of the work or die is desirable. Furthermore,neither the drawing lubricant nor the surface of the metal shouldcontain any solids capable of scratching the surface of the metal. p

An object of the present invention is to provide a method of drawingmetal wherein the metal is lubricated throughout all temperatures belowits welding point so thatrelaliv'ely smooth working of the metal isfacilitated and there is no galling, seizing, or scratching of the metalor die and a smooth shiny surface is produced on the metal.

A further object of the present invention is to utilize a drawinglubricant containing ingredients which function to provide lubricatingand cooling properties throughout the different temperature ranges bytheir ability to melt and How under frictional heat and to provide amethod of drawing metal whereby the workpiece and die are subjected to astepwise lubricating action of materials which function to give optimumlubricating properties throughout the difllerent temperatures.

Another object is to provide a process of drawing and forming metalwherein a smooth finish is obtained on the drawn article and wherein theresidual fusible integral film on the metal forms a desirable base forpaint or enamel coatings so that the drawn article may be paintedwithout the necessity of first cleaning the surfaces thereof or so thatthe fusible lubricant coating acts as a prime coating to providesuperior adhesion of subsequent paint or lacquer films.

In accordance with the present invention, I form an integral meltablefilm directly on the surface of the workpiece, and coat this with asuitable organic binder through which is disposed pigments ofdistributed melting points. The integral coating formed on the surfaceof the work and the pigments in the binder are of materials having ahardness less than 5 on Mohs scale and melting at temperatures belowthat of the die or the workpiece, whichever melts at the lowertemperature. Likewise, the organic binder melts or decomposes attemperatures below that of the fusion of the fusible pigments. Themelting points of the integral coating, organic binder, and incorporatedsolids are determined and arranged or graduated so that they melt insuccessive temperature ranges and there is a plastic lubricant btweenthe die and workpiece at all temperatures and stepwise lubrication isachieved.

The process thus embraces three basic, co-acting factors. In the firstplace, there is an integral coating formed directly upon the work. Inthe second place, an organic binder is disposed over the work. Andthirdly, meltable pigments are dispersed in the organic binder tofurther lubricate and facilitatedrawing and deformation of the work.Inthis way, the work is lubricated and protected throughout the drawingor forming process and superior draws are made possible.

Various materials and processes can be used to form the coating directlyon the work surface'and several resultant coatings can be employed. Thequalifications of the integral coating or fixed film are that it musthave a hardness less than 5 on Mohs scale and that it will be plastic attemperatures below that at which the work or die welds.

INTEGRAL COATINGS The formation of integral coatings on ferrous metalsis brought about by an unusual electrochemical phenomenon. The usualcorrosion of metals involves a well understood galvanic action betweenlocal cells or couples on the metal surface in which specific areas ofthe metal become anodic because of differences in chemicalcomposition,intergranular strain, or local oxygen concentration, and iron goes intosolution and the equivalent hydrogen ions are discharged at the lessreactive cathodic areas.

The formation of tarnish films and integral coatings on polyvalentmetals involves the Wagner electrolytic theory. C. Wagner studied thisphenomenon and proposed an explanation reported in the transactions ofthe Faraday Society 34,851 (1938) and elsewhere. Unlike the localgalvanic cells existing in the usual corrosion of metals, the corrosionproduce or tarnish film is built up by a mechanism wherein themetal-to-film interface becomes the anode and supplies cations andelectrons for outward diffusion, and the attacking filmsubstance-toenvironment interface becomes the cathode and suppliesanions for inward diffusion. The growing film thus acts as both theinternal and external circuits of a closed cell. The internal cellcircuit is made possible by the insoluble iron. compounds acting as asemi-conductor, while the conducting electrolyte in the film pores andcapillaries furnishes an external circuit. The Wagner tarnish mechanismrequires an attack by a diacidic metallic precipitating reagent in orderto form the semi-conducting metallic component of the internal circuit.Thus, when the polyvalent metal is ferrous, the integral coating willalways contain iron salts. The cathodic film-to-solution interfacecontains .the discharging hydrogen, so that any depolarizer in the'solution. effectively accelerates the coating action.

The principal object of this invention is to utilize the Wagnermechanism to convert an otherwise refractory metal surface into anintegral film of suitable compounds that will absorb and tenaciouslyhold a thermoplastic lubricant filmcontaining other fusible pigments.

When such a film is to be formed in aqueous media, the diacidicprecipitating reagent can be selected from the difluorides,.the variousdihydrogen phosphates, the dicarboxylic organic acids, and the diabasicinorganic sulfur containing acids ranging from hydrogen sulfide throughsulfoxylic to the various polythionic acids.

'Tarnish films of mixed oxides are also formed in the gaseous phase bythe Wagner mechanism but I prefer to form sulfide layers, because oftheir fusihility. I

Another modification of. Wagner film formation involvesthe use of moltensalts containing active sulfur which also produces fusible iron sulfidelayers on ferrous metals that can be used as a lubricant undercoat.

IRON SULFIDE COATINGS The most versatile lubricant base integral coatingis that consisting principally of iron sulfide since it can be appliedin either aqueous, gaseous, or molten salt media.

When ferrous metals are to be coated with a fusible integral ironsulfide film in aqueous media, I utilize an acidic solution containingcolloidal sulfur, sulfur dioxide, and a mixture of polythionic acids.Such a solution can be prepared by the acid decomposition of unstableinorganic sulfur compounds by any of the following methods: i

1. Sodium thiosulfate or sodium polythionates decomposed by preferreddibasic acids which'are also coating agents. I x I 2. Decomposition ofequimolar H25 and S02 in aqueous acid solution to give Wackenroder'ssolution.

3. Hydrolysis of sulfur mono-chloride emulsified in a dibasic acidsolution to form polythionic acids.

4. Interaction of wettable sulfur and sulfur dioxide in a solutioncontaining a dibasie coating acid.

Integral ferrous sulfide films can also be formed on *sull or ironhydroxide coated ferrous metal by converting the hydrated iron oxidefilm to iron sulfide by dipping in a hot aqueous alkaline polysulfidesolution.

When ferrous metals are filmed with a layer of sodium thiosulfate or anequivalent decomposable sulfur salt, the metal can be coated with anintegral coating of iron sulfide by heating the filmed metal above theinitial meltingpoint of the hydrated salts which melt in their waterofcrystallization. Likewise, a molten salt bath containing' activesulfur can be utilized. When ferrous metals are to be coated with asulfide coating in gaseous media, a reducing atmosphere containingsulfur vapor is used and either th'e'bare iron surface is filmed withiron sulfide or the' hot mill scale on the metal surface from previousoperations can be converted to iron sulfide to act as a lubricantundercoat using a sulfur or phosphorus halide catalyst if required.

4 INTEGRAL PHOSPHATE AND OXALATE COATINGS ammonium dihydrogen phosphate.The second type is a heavy coating of about 200 to 1000 mg. per sq. ft.of mixed zinc and iron phosphates formed by treatment of steel surfacesin hot aqueous acidulated l to 5 per cent zinc dihydrogen phosphateaccelerated by a strong oxidiz- 7 ing agent such as chlorate,persulfate, hydrogen peroxide, or a mixture of nitrate and nitrite. Thephosphate coatings from these baths are heavier because free acid isconsumed by the iron surface acting as anode in the Wagner mechanismthat zinc phosphate precipitates upon the work along with the ironphosphate formed by the neutralization of the free acidessential to zincphosphate solubility. The amount of iron dissolved as anode in a zincdihydrogen phosphate bath has been reported by Murphy and Streicher whoshowed.(Proceedings Amer. Electroplaters Soc., p. 288; 1948) that anaverage phosphate coating from a zinc phosphate bath had a coatingthickness of 0.055 mm. which represented an etched depth of 0.050 mm.and a dimensional increase of only 0.005 mm.

When a phosphate undercoat is desired as a component of my stepwiselubricant film, I can use any of the various proprietary coating bathsin the patent literature such as those of Tanner and Lodeesen U. S.Patent No. 1,911,726,

or Romig Patent No. 2,l32,439; or I can use certain novel baths usingRoussins salts or nitrosyl chloride as the accelerator; or a novel bathof immersion copper plate codeposited with iron phosphate which actsboth as a galvanic accelerator and v a lowv frictional surfacecomponent.

Similarly, the proprietary oxalate coating baths such as that of Curtinand Kline U.,S. Patent No. 1,895,568, or of Tanner U. S. Patent No.1,911,537 can beused to obtain an integral oxalate coating as acomponent of a stepwise lubricant film. A novel method of obtaining anintegral oxalate is to thermally decompose an aqueous layer of ferricoxalate, calcium chloride and oxalic acid uponthe work to form aninsoluble film of mixed calcium and ferrous 'oxalates.

' When an oxalate under'coating is used as a component of a stepwiselubricant, it is most desirable to convert the film to a more fusibleform by dipping the coating in a hot alkaline aqueous solution of asulfide, borate, or phosphate to convert iron oxalate to a fusible ironborate, sulfide, or phosphate and to a meltable sodiumoxalate which inturn is thermally decomposed to fusible sodium formate and sodiumcarbonate under frictional heat.

The various methods of converting a refractory ferrous metal surface toa fusible iron compound which will imbibe and anchor a stepwiselubricant composition is illustrated in the following'examples:

A sulfide coating bath for stainless steel was made up as follows:

EXAMPLE I,- -SULFIDE COATING ON STAINLESS STEEL The sodium thiosulfatewas added to the aqueous bath after it was made up, and it was convertedto' polythionic acids, sulfur dioxide and colloidal sulfur inequilibrium, to make a sulfide coating bath. Various other additionswould produce the same polythionic acid equilibrium. that I surface.

is required for an iron sulfide coating bath, but the thiosulfateaddition has the advantage of'conveniencc.

The stainless steel coating bath is heated to between 115 F. and 135 F.a lift of previously pickled 18-8 stainless steel tubes were immersed inthe bath for six minutes, and removed to drain the points of the tubesto assure inside diameter coating, and the tubes again immersed in thesolution for six more minutes to com- VAIOR PHASE SULFURIZING Vaporphase or gas-sulfurizing reaction can alsobe used to coat the metal witha sulfide film. The reaction is carried out by subjecting thework tosulfur or sulfur containing compounds in a heated reducing ornon-oxidizing (inert) atmosphere. The sulfur can be applied as a coatingbefore heating the work, or bled into the reducing atmosphere from aseparate vapor generator. Hydrogen, hydrocarbon gases, carbon' monoxide,ammonia or the oil vapors or other vapors commonly used for reducingatmospheres in the bright annealing of ferrous metals are satisfactoryas reducing atmospheres during the reaction between sulfur and theferrous metal. The attack of iron by sulfur begins at about 400- F. andincreases rapidly up to about 950 F.

, One advantage of my vapor phase sulfurization treatment in a reducingatmosphere is that I may utilize metalfrom which the scale has not beenremoved as well as clean metal. Instead of removing the scale with anacid or surface treatment, I am able to convert the scale directly intothe desired ferrous sulfide. A trace plex layer of iron sulfide on theferrous surface after a few minutes exposure.

ill

of water or water vapor to initiate the reaction is usually necessary inorder to obtain efficient reduction of the iron oxide of the scale toferrous sulfide. With high chromium and stainless steels, a catalystsuch as phosphorus, halogen, 'a phosphorus or a sulfur halide or othersuitable corrosive compound containing such elements is desirable topromote the reaction.

- The atmosphere itself should be a reducing or a neutral, non'oxidizingatmosphere. An oxidizing atmosphereforms hard, undesirable ferric oxideand sulfide compounds such as iron pyrites or magnetic iron scale.

EXAMPLE II.SULFURIZING IN AMMONIA ATMOS- PHERE Hot rolled 18-8 stainlesssteel rod coated with mill scale is'placed in an annealing furnace in anatmosphere of 75 per cent disassociated ammonia and 25 per cent nitrogenand'heated up to 1250 F. Free sulfur vapor is introduced from agenerator containing boiling elemental sulfur and sulfur monochloride(liquid SzClz) is separately dripped into the furnace to furnish asulfur halide catalyst to reduce the scale and assist its conversion toiron, chromium and nickel sulfides. -The furnace temperature is keptbetween 1250 and, 1800 F. for 10 to 25 minutes and then the work isremoved. It is found to be coated with a relatively thick, fixed layerof mixed metal sulfides.

EXAMPLE III.-SULFURIZING IN BURNER GAS ATMOS- PHERE The work is placedin an atmosphere of exhaust burner gan containing nitrogen, CO2 andexcess air and heated up to between 900 and 1300? F. Sulfur vapor from avaporizer is bled into the mixed stack gases where it combines with theoxygen of the excess air to produce a reducing and sulfurizing'atmosphere to form a com- SULFURIZING BY THERMAL DECOMPOSiITION OF ASULFUR COMPOUND Another method of forming an integral ferrous sulfidecoating upon ferrous metals is to cover the work with an alkaline layerof a sulfurizing agent and then heat the work in an annealing furnace,or a flash baker.

After steel has been hot rolled and initially shaped. the pieces have tobe annealed to restore the ductility for further cold work. In the vastmajority of cases, the anneal is performed in an uncontrolled furnace atatmospheric pressure so that the work becomes heavily scaled and must bepickled before further cold work or drawing can be performed. When thework is covered with an alkaline film of a sulfurizing agent and heated,however, the heavy scaled layer on the hot rolled steel is converted toferrous sulfide and the work made ready for cold drawing and shaping. Inthis way, I eliminate the pickling step and utilize the annealing stepto deposit a layer of ferrous sulfide on the metal.

The alkaline sulfurizin'g agent consists of a fusible alkali metal saltand a reducible sulfur compound that will convert the ferrous layer toiron sulfide and alkali ferrates when heated to a red heat and thusgivean integral coating which can be cold worked without harming the workingtools and dies. The magnetic iron oxide usually formed during hotrolling and annealing is highly abrasive to tools and dies. In additionto the fusible alkali salts and sulfurizing agents, fusible pigmentscanbe incorporated or dispersed into the alkaline layer. A combination ofpigments with analkali coating is preferred for carbon steel while anunpigrnented film can be used for stainless steel.

A suitable alkaline type coating is given below. The mole fraction ofeach chemicalis given so that chemically equivalent compounds can bereadily substituted by anyone skilled in the art.

EXAMPLE IV.-COATING FOR SULFURIZING DURING ANNEAL Typical Mix, Parts DryWt.

Sodium hydroxide Sodium carbonate... Sodium thinsulfate SodiumMetasllicate 0r Trisodium phosphate Sulfur Starch...

This ismade up into a 15 per cent to 33 per cent aqueous solution andapplied to the work by dipping tional complex chemical reactions whenthe work is J heated. Iron sulfide and alkali ferrates are formed andwhen phosphates are used as the fusible salt, it is believed that somethiophosphates are formed. When sodium silicate is used as the fusiblesalt, certain ultra marine type silicates are formed.

The work is dipped in the solution which is heated up to -200 F. and thehot solution allowed to dry on the work before being placed in anannealing furnace or passed through a continuous open flame gasannealer.

EXAMPLE V.- INTEUBAL IRON FLUORIDE COATING Another readily appliedintegral coating is an iron fluoride layer. This is applied by immersingthe work (NaH2PO2.HzO)

or sodium sulfite in each gallon of water. Immerse the work in thissolution maintained between 120 and 160 F. for to 15 minutes and thendry. This will form an adherent integral coating of iron fluoride,containing some ferrous phosphite or sulfite.

INTEGRAL PHOSPHATE COATINGS A predominately iron phosphate film can beformed on ferrous stock by dipping it in solution of a diacidicphosphate such as sodium dihydrogen phosphate, potassium .dihydrogenphosphate, ammonium dihydrogen phosphate, magnesium dihydrogen phosphateor calcium dihyrogen phosphate accelerated with an oxidizing or rcducingagent. Suitable oxidizing agents are sodium chlorate, sodium nitrite.sodium nitrate, hydrogen peroxide, potassium persulfate, picric acid,quinone, and various other chlorates, bromates, and iodates. Likewise,suitable reducing agents are sodium sulfite, sodium thiosulfate, andsodium phosphite.

EXAMPLE VI.-IRON'PHOSPHATE COATING Parts (NI-I4) H2PO4 75 03C]: 11 H2ON.-. 14

Thisis made up 5 per cent by volume into an iron phosphating solution.This bath could be accelerated by bubbling in gaseous nitrosyl chlorideor by adding aqueous nitrobet'aine, or NOCl amine complexes or Roussins'.salts which are nitroso complexes of iron and sulfur.

These are further described on page 678 of the Fritz Ephraims InorganicChemistry, 4th ed. (1943). This is an improvement to the Glen L.Williams Patent No. 1,514,494 which disclosed phosphating solutionscontaining an unst'ablc mixture of aqua regia and Steifans sugar beetwaste asv accelerators. Zinc di-hydrogen phosphate or manganesedihydrogen phosphate can be used in place ofthe mono-ammonium phosphateshown in the foregoing example if a heavier mixed zinc o manganese andiron phosphate is required.

EXAMPLE VII.-COPPER IMMERSION PHOSPHATE Per cent Mono-sodium phosphate 3Copper sulfate 0.1

This bath should be maintained at around 180 F. The integral coating ofimmersion copper mixed with copper and iron phosphates formed byimmersing the work in this bath forms anexcellent base for anysubsequent' lubricant coating.

. EXAMPLE VIII.ZINC PHOSPHATE BATH Solutions of manganese phosphate,cadmium phosphate, and zinc phosphate will form heavier integrallubricating'coatings comprising iron phosphate when accelerated withsodium nitrate or nitrite, hydrogen peroxide, or sodium chlorate thanthe previous iron phosphate Ecoatings. Such heavy coatings are obtainedby various prior art methods such as the following:

1 g Per cent Zn: (HzPOOi Q. 3 NaClOa 0.6 HaPO4 0.5

Maintainvthis bath at 160 to 180 Rand immerse the pickled stock for 5 tominutes to form an integral coating of mixed iron and zinc phosphates.

Phosphate coatings are particularly valuable for drawing and coldworking of metal because after the drawing or cold working has beencompleted, the phosphate coating forms a protective and anti-corrosionlayer. It is also a very good base over'which to apply the binders usedin my stepwise lubricants. The phosphate baths,

however, do not coat over stainless steel, so that oxalate, sulfide orfluoride baths must be used on these alloys.

INTEGRAL ORGANIC ACID COATINGS Other integral coatings can be formed onthe metal by treatment with selected organic acids. This process isfully explained in Patent No. 1,911,537 to Robert Tanner. Briefly, itconsists of immersing or spraying the metal with a hot solution ofaliphatic series acids with dicarboxyl groups or hydroxydicarboxylgroups or with aromatic series acids with one carboxyl group orsulphonic acids. The reaction is preferably accelerated with anoxidizing agent such as manganese dioxide or sodium sulfite and varieswith each acid used. The best-of the pure hot solutions are oxalic,malonic, tartaric, salicyclic,

gallic, and diglycollic acids.

The coatings formed are mainly iron salts of the acids used. Thus oxalicacid forms ferrous-ferric oxalate, tarbonate; it is preferable to rinsethe integral organic iron coatings in hot aqueous solutions of analkaline sulfide, borax, or disodium phosphate to both imbibe fusibleflux salts and to form fusible iron salts and fusible sodium salts byion exchange.

EXAMPLE IXOX.ALATE COATING BATH Prepare an aqueous solution of one partof sodium sulfite to fifteen parts of oxalic acid with preferably asmall amountof manganese dioxide, one fortieth as much manganese dioxideas oxalic acid being a good ratio. The work is clipped in thissolution'at room temperature or slightly warmer, and the coating shouldform in a minute or so.

MELTABLE PlGMENTS FOR STEPWISE LUBRICATION According to my presentinvention, the fixed integral films previously described are coated witha binder through which is distributed various meltable pigments. Thepigments must have a Mohs hardness of less than 5 and melt below themelting point of the work or the die, whichever is lower. The pigmentsgenerally melt above 500 C. and arevarious soft and fusible metalcompounds.

The pigments in each lubricant are selected in relation to the integral'filrn and binder so that there is effective stepwise or graduatedlubrication between the work and die throughout the great portion of thedrawing operation. "Thus, the binders usually melt below 200' C. tofurnish initial lubrication, so that the pigments selected should meltbetween 200C. and 1300- C. or

roughly, the melting point of the work if it is low carbon The choice ofthe best combination of integral coating and stepwise lubricant iscontingent upon the amount of reduction required in the formingoperation. In general, a light reduction of to percent can be taken uponwork coated with a conventionai iron phosphate:v coating of 50 to 150mg. per sq. ft. or the equivalent light sulfide or oxalate coating. Fora heavier draft of to per cent, a heavy zinc (and iron) phosphate, ironsulfide, or iron oxalate coating of 200'to 1000 mg.

a greater reduction of, for example, 30 to 40 per cent it I would bepreferable to apply the heavier zinc phosphate coating or its equivalentiron sulfide or oxalate layer, 1

and to film the heavier undercoating by immersion in a hot aqueoussolution containing 3 .ounces per gallon sodium tallow soap, 16 ouncesper gallon borax, and 2 ounces per gallon precipitated chalk, or anequivalent fusible pigment. The precipitated chalk reacts in the hotborax solution to form a fusible shell of sodium carbonatev and calciumborate over each minute particle and is thus equivalent to a fusiblepigment.

If it were necessary to draw this same workpiece to an extreme reductionof 50 to 65 per cent, or to make more than one reduction withoutrecoating the piece, it would likewise be desirable to apply a heavyzinc phosphate or an equivalent heavy undercoating, but an initial waterinsoluble stepwise lubricant would be first applied to the heavyintegral undercoating as a solvent paint or water emulsion consisting ofthinner, a thermoplastic binder, and fusible pigments. When 'thisinitial water insoluble stepwise lubricant film has dried or set-up, thework is then coated with an aqueous soap and borax type lubricant, anddrawn to the extreme reduction. When such duplex lubricant layers areused in severe or multiple drafting, the water'soluble stepwiselubricant is rolled back into the die throat and the water insolublethermoplastic binder and fusible pigments are forced into the drawnsurfaceto prevent any metal-to-metal contact, and tol'eave aresidualstepwise lubricant film that can be recoated'with the water solublestepwise lubricant, and again drawn. This duplex method is shown inExamples XV and XVI.

As a production cost factor, any appreciable increase in drawing speedor reduction will absorb any reasonable expenditure for properly coatingthe work and using the best suited lubricant.

Table L-Fusible Pigments Mohs Hardness Melting Formula Point,

Copper Powder G ccaenouvoocoooenooo mate. Lend Moldvabdate (wulienite).Leadoxi (llthar: Load phosphnte....* lend metullicate W ana Manners M B.lulfltle (Vermilion). Me chloride (calomel) Mal eoride c llulfld2118(P0l)! .I:

Various binding materials are usable in conjunction with the presentinvention. The binder serves as a vehicle for incorporating the meltablepigments to distribute them uniformly over the work surface and toprotect and lubricate the inner integral film of phosphate or sulfide byacting as an initial lubricant between thework and die over the lowertemperature ranges.

The binding material is preferably a thermoplastic natural or syntheticresin having a melting or softening point below 300 C. The choice ofvehicles and pigments is usually determined by the expenditure that canbe made and the severity of service required. When the service is not sosevere and the expenditure is limited, a heat labile binding materialsuch as the organic colloids which decompose at relatively lowtemperatures may be used and the principal reliance for lubricationbased upon the fusible pigments. On the other hand, when there is severeservice and suitable expenditures can bemade, a fusible natural,synthetic or resinous material is preferred. Corrosive vehicles, i. e.,those containing sulfur or chlorine, such as solutions or dispersions ofchlorinated diphenyl (Arochlor), chlorinated rubber (Tomesit), ethylenepolysulfide polymers, chlorinated paraflin, 2- chlorobutadiene polymer(neoprene) and vinyl chloride are especially desirable in that they tendto bond directly to the metal through their polar linkages. In addition,their decomposition under frictional heat will cause the formation of afusible iron chloride or sulfide as a secondary lubricant.

In lubricating compositions of the present invention, the proportions ofpigment and vehicle may be varied widely to obtain the desired fluidity.Usually, it is preferable to have 10 to 30 parts of vehicle or binderfor each 100 parts of composition, the remainder being pigment andsolvent. The vehicle is thus considered as the residue in the fixed filmafter evaporation of the solvent. The pigments generally comprise fromtwo to five times the amount of the vehicle. p

Examples of suitable natural and synthetic thermoplastic resins whichmay be utilized in conjunction with the suitable fluidity-impartingagent, such as a solvent, plasticizer, or dispersing mixture arelistedbelow:

Table II Soite thil e nge, C.

Resins-S thetlc: Acry e ester polymers (polymethyl methaerylate type105-120 Allryd type, non-oxidizing (glycerol-phthnlic anhydride -1l5 yitype, oxidizing (unsaturated fatty acids)... -100 .Alkyl type, modified(rosin 80-110 Cellulose acetate (Aoeto-butyrate) 00-120 Gellulosenitrate; Coumnrona-lndeno. 75-100 yclopsrsflln (napthenes or completelysaturated carbocyclic compounds) -110 Ester Gum 70-100 Ethylcellulose"... 100-330 Styrene polymer 8 Toluene suitonamide iormnldehy70-100 Polyvinyl chloride.

Wares, natural 0...... 40-80 Waxes, petroleum 25-60 All of the bindersor resins listed above in Table II' are meltable and thus form anadditional lubricant for" the work as the deforming operationprogresses.

The resins listed below in Table III are suitable for use with asolvent, plasticizer, or dispersing mixture to give 75 a binder, butthey are thermosetting at higher temperatures and do not melt so that anadditional lubricant should used with them.

Table III.Thermosetting Resins Melamine or urea-aldehyde polymersCasein-formaldehyde Phenol-formaldehyde Water soluble binders suitablefor use with other water soluble or water insoluble pigments are listedbelow.

These binders are divided into two groups, the lubricating or meltingbinders and the non-lubricating or .charring binders which carbonize ordecompose at elevated tempcratures.

Table ]V.-=-Water Soluble Lubricating Binders Carbowax (a polyalkyieneglycol ether) Glycerol and glycol borates and phosphates Glycol stearatePolyalkylene glycol oleate or stearate Sodium palmitate Sodium stearateSodium oleate Water Soluble Non-Lubricating Binders Ammonium alginateCasein Dextrin (starch gum) Gelatine and glue Gum arabic, tragacanth,etc. Methyl cellulose Pectin Polyvinyl alcohol Hydroxy ethyl celluloseSodium glycolate Sodium resinate 1 Water Soluble Non-Lubricating Binders"Sodium naphthenate Starch When a water soluble, non-lubricating binderis used it is also necessary to use some sort of additional lubricam forthe lower temperature ranges (100-400' C.). Good lubricants for thispurpose are the various commercial drawing and cutting oils, lubricatingoils, soaps of all kinds, especially high titre, high tallow soaps, soapand borax mixtures, and the various natural and synthetic waxes. f

CONCLUSION or deforming of metal. It is understood that the inven-- tionis by no means limited thereby and that these are only typical formulasselected from the wide range of combinations of integral coatings andlubricants such as are above described.

EXAMPLE X.THERMALLY FORMED OXALATE A solution of the followingcomposition was made up: i 1 Oz. per gal. Ferric oxalate 1.0 molar 50Oxalicacid 1.0 molar 17 Calcium chloride 1.0 molar 17 The'above solutionis heated to 115 F. and a yoke of pickled stainless steel rod immersedin the solution, and the excess solution allowed to drain otf after atwo minute immersion. There is no noticeable coating action In addition,the relative cost of the compoundin such a short immersion at such alow'temperature,

but a coating of insoluble ferrous and calcium oxalates are formed whenthe oxalate film is dehydrated in the flash baker. The film of insolubleoxalate is firmly bonded to thestainless surface. The dried oxalatecoated wire is thereafter drawn through a plurality of successive dieswith no further treatment by utilizing a stepwise box soap powdercontaining a flux and mineralizer and having the following composition:

Sodium stearate 45 per cent molar" Sodium sulfite 12 per cent 1.10 molarBorax 38 per cent 0.10 molar Moisture 5 per cent This soap is made bycrutching ground borax glass and anhydrous sodium sulfite into thesodium stearate after saponification to remove water and then pouringthe molten mixture into frames, and grinding the" dry soap into apowder.

EXAMPLE X I.WATER cam As aforementioned it is possible to form anintegral ferrous sulfide coating on articles to be drawn with I areagent that will become also a water soluble stepwise lubricant, whenthe residual film is dried on the work. Such a combination coating andlubricating bath can be made up by dissolving 8 to oz. per gallonof thefollowing composition in hot water: I

Diethylene glycol stearate or sodium stearate; 20 per cent Starch orpolyvinyl alcohol 10 per cent g Sodium thiosulfate, NazSzOaSHaO 0.16molar-.. 40 per cent The bath is heated up to -200 F. and the degreasedcarbon steel work immersed in the hot solution for aboutfive minutes,during which time a black iron sulfide film is formed on the surface bythe polythionic acid decomposition products. The work is removed, thendrained and dried, and the film remaining on the work is a step wiselubricant by virtue of the polar stearate,'protective colloid, andfusible fluxsalts comprising the dry homogeneous film. The reactionswhich take place are p as follows:

4NB5B3O: 12331301 2NBB4O1 10320 4Br13 O: S iNaHSO;

. Pclythiomte (2) Decomposition on drying: 2N8aBrO1 H5301 48 iNBHSO:

' 3NMB|O1 Nest +.4so, 1 (gas) The dried film therefore contains sodiumtetraborate and sodium tetrasulfide in additionto the protective col Iloid and polar stearate lubricant. The coated metal is thereupondeformed by passing it through a die.

EXAMPLE XII.-WATER SOLUBLE PBOSPHATING LUBRICANT Combination coatingreagent and stepwise lubricant similar to that in Example X can beformulated to form an integral phosphate coating on carbon steel, andalso deposit a stepwise lubricant film. Such a bath can be prepared bydissolving from 8 to 20 oz. per gallon of the following dry powder.

. Parts Diethylene glycol stearate or sodium stearate 20 Starch orpolyvinyl alcohol 10 Mono-sodium phosphate, NaHzPO4--0.5O mo1ar... 60Sodium thiosulfate, NazSzOa.5l-IzO-O.l7 molar 40' The bath is heated upto 180 to r. and the de-' greased articles (steel tubes in thisinstance) to-wbe phos' I phated arefimmersed in the hot solution forabout five minutes, during which time an integral iron phosphate.coating is formed by the mono-sodium phosphate -ac- SOLUBLE SULFIDINGLUBE! I NBIBSOI SNltHP ZNaHgPOm NBBBO: 8

R Coating Acid Depolarizer (2), Decomposition on drying:

N81HP04+ 2NaHzP04 NaHSO: S

ZNMHPO; N8]? 03 so! T (855) SZE:O The dried coating film thereforecontains two mols of disodium phosphate to one of mono-sodium phosphateso that I have an alkaline flux in addition to the colloidal sulfur,protective colloid and polarstearate lubricant.

The articles thus coated with the integral undercoating of ironphosphate and with the superimposed fixed film. of water solublestepwise lubricant is thereupon drawn through suitable drawing dies toprovide a reduction in size. Several passes are bad without intermediatecoating and the articles have a bright shiny surface. This combinationof iron phosphate undercoating and water soluble stepwise lubricant isvery satisfactory for drawing articles that are to be electroplated, andwhich must be grease free and easily cleaned. I

It should be pointed out that both ofthe water soluble stepwiselubricants shown in Examples XI and XII tend to produce alkaline bathsunder continued use due to the neutralizing action'of the iron beingcoated, and the break- A water slurry containing 8 oz. per gallon of asodium stearate soapand 8 oz. per gallon of calcium borate pigment isheated to 190 F. and steel blanks coated by immersing them five minutesin the soap-calcium borate slurry and the blanks drained and dried by ahot air blast. The filmed blanks are then deep drawn in a hydraulicpress operated die, producing shells with an excellent finish. The drawnshells are then cleaned by swilling off in hot water.

EXAMPLE XIV.-SULFURIZING SOAP TYPE LUBRICANT The work is dipped in thestainless steel coating solution of Example I, left in it for aroundfive to fifteen minutes during which time a black sulfide coating isformed onit. It is then dipped in a per cent water solution of thefollowing dry-powder, dried, and de@ formed by drawing through a die.

Molarlty Percent EXAMPLE XV.--EMULSION' PAINT LUBRICANT Pounds/partsAntimony oxide (M. P. 315 C.) 164 I Zinc borate (M. P. 980 C.) 493Linseed oil modified Alkyd resin 206 Cobalt Linoleate (6% cobalt) 2Qleic acid 14 t Casein ..;f 21 Z-amino methyl propanol 7 Algin 3 Water392 vThe above ingredients are mixed in any desired order to provide anaqueous emulsion paint.

Low carbon steel sheet is first cleaned and then givena phosphatic paintbase coating by treatment in a bath of calcium dihydrogen phosphate. Thephosphated sheet is then painted with the antimony oxide-zinc boratepaint given above. When the painted sheet is thoroughly dry and hasformed a fixed solid film it is immersed in a solution of hot paraffincontaining 30 per cent calcium stearate. This completely Waterproofs"the sheet and leaves a lubricatingwax protective layer on the paint.The sheet is then deep drawn into a cylinder on a hydraulic press usinga flowed water coolant and lubricant containing 2 oz. per gallon ofsodium stearate and 2 oz. per gallon of borax. The drawn-cylinder has ahighly lustrous finish, free from galling or scratch marks .so that adesirable finish may be applied by merely a dip or spray with a thinclear lacquer. This stepwise lubrication'can be shown to consist of thefollowing progressive melting cooling sequence:

Castor oil 4 Toluene S4 Hy-flash naphtha "l0 Butanol 8 Ferrous sulfidepigment (M. P. 1193 C.) 24 Nickel sulfide pigment (M- P. 797 C.) 24

The two sulfide pigments are milled into the heated ethyl cellulose andthe mixture thus formed together with the rosin is dissolved in thesolvent. The metal to be worked is first placed in a furnace and heatedup to 900 F. in a controlled atmosphere of cracked natural gas. When themetal, has' reached a red heat sulfur vapor is introduced into thefurnace in a sutficient amount to produce a black color over the surfaceof the metal. The metal is cooled in a reducing atmosphere and thencoated with the above pigmented composition. The metal is then deepdrawn into a cylinder on a hydraulic press using as a fluid flowed overthecoated black an aqueous solution of coolant and lubricant of fourounces of diglycol stearate per gallon of water. The article producedhas a black, shiny protective surface which can becoated with paints asdesired without cleaning.

EXAMPLE XVII.-CHLORINATED RUBBER LUBRICANT A chlorinated rubber,thermoplastic paint is made up having the following composition:

Parts Chlorinated rubber 20 Chlorinated diphenyl- 8 Turpentine 3SHy-flash naphtha 35 Butanol 2 Cuprous chloride pigment 40 This paint isused to coat a stainless steel rod pre viously sulfurized as by ExampleII. Cuprous chloride by the thermal decomposition of the chlorinatedrubber The rod is drawn to 25 per cent reduction and still has a brightfinish after drawing.

EXAMPLE XVIII.EMULSION PAINT Per cent dry weight Calcium resinateCalcium stearate 4 Paraflin wax 10 Sodium stearate 3% Sodium resinate 3Ferrous sulfidc.. Calcium sulfate 30 NaaBs'OmlOI-EO This is to beconsidered as only illustrative of the emulsions that can be used. 7

EXAMPLE XIX.-BUMPER BAR FORMING LUBRICANT Cold forming has replaced theformer hot forging of automotive bumpers, so that the bumper bar stockcan be machine polished in the flat, and the polished stock phosphatedand coated with a water soluble stepwise lubricant that can be readilycleaned off so that no defective nickel plating will be caused by 'anylubricant residues. Since the deformation in this operation is great, itis preferable to use a medium phosphate coating, but since productiontime is of the essence, it is best applied by an accelerated zincphosphate bath such as that in' Example VIII.

After the bumper stock is phosphated and rinsed, a stepwise lubricant isapplied by roller coating, and the .applied'lubricant film quickly driedby hot air blast or an infra red drier. A satisfactory composition isthe following:

Soluble Bumper Lubricant Weight Molarity Percent Comp.

Sodium tallow soap 0.15 10 CarbowexBOOO 0.001 0 Potassium carbonate K 000.15 20 Borlc acid HEB 0| 0. 10 20 Borax NegBrOnlOIhO..- 0. 10 38 Theabove dry powder is made up into-a warm soft water solution at aconcentration of about 14 oz. per gallon and the solution maintainedbetween 160 and 175 F. for roller or drip application. This typeoflubricant is disclosed in the Orozco and Henricks PatentNo. 2,469,473.

' EXAMPLE Xx.-'-s0AP AND BORAX LUBRICANT Carbon steel blanks for deepdrawing were cleaned-in an alkaline cleaner, rinsed, and dipped in cold15 per cent'muriatic acid to give a minute etch, again rinsed,

and then coated in the copper immersion accelerated EXAMPLEXXI.--ALKALINE RINSE .Deep drawing stock was phosphated with a lightiron phosphate coating in the-ammonium dihydrogen phosphate bath inExample Vl,-which bath also contains calcium salts as well as some ironsalts held in solution by the chloride ion as the iron nitrosyl complex.In

16 order to augment the thin iron phosphate coating and to gainadditional film pigments, the coated work was not water rinsed in theusual manner. Instead, thecoated work still filmed with the coatingsolution is dipped in a hot still solution of 4 to 6 ozs. 1 gal. ofdisodium phosphat e, and held in the solution for three minutes so thatall of the calcium and iron absorbed in the unrinsed coating will beprecipitated as insoluble phosphate. The sodium phosphate treated workwas then coated in the following sulfiurizing soap lubricant, stillwithout rinsing.

Mole-ritzy {Egg The work thus given the alkaline phosphate treatment hadan improved undercoating film as evidenced by fact that the work sotreated could be drawn to -a greater reduction than identical work coldwater rinsed after phosphating and coated with the identical lubricant.

EXAMPLE XXII.-SULFURIZING IRON HYDROXIDE COATINGS Wire rod can be sull"coated by allowing freshly pickled carbon steel to rust in the air whilewet with water ora weak salt brine. Stainless steel can be provided witha hydrated oxide layer by dipping clean pickled stock in a fused sodiumhydroxide bath containing about 10 percent sodium nitrate and maintainedat 900 to 1000 F. p

In either case, the hydrated iron oxide is converted to fusible ironsulfide mixture by immersion in' a boiling polysulfide solution made upfrom 1 to 3 pounds per gallon of the following calcium sulfide coating:

The brown iron hydroxide layer is thus converted to a black iron sulfidemixture forming anintegral fusible coating over the work. The rod isremoved from the bath after a 3 to 5 minute immersion, and the calciumchloro-sulfide layer dried on the work in a flash baker to become a limesubstitute. The coated rod is then drawn through a stepwise lubricantbox soap such as that disclosed in Example X. The finished wire has abright smooth black surface completely free of scratches or irnbeddedlime particles.

WIRE

Carbon steel wire is sull coated in the same manner as the previousexample or stainless steel wire is given an oxide coating in a fusedcaustic bath, and rinsed ofl and dipped in a hot sulfurizing soaplubricant solution such as that disclosed in Example XIII. The coatedwire is darkened by immersion in the hot solution, but the hydroxideundercoating isnot completely blackened until the soap film is dried ina flash baker after being drained and air dried. a.

Theintegral sulfide coatingand water soluble stepwise lubricant filmformed in this 'manner is drawn through a stepwise box soap lubricant ofthe following com- The wire so treated and drawn has a bright grayfinish free of any scratches or drawn in lime particles.

While in the aforementioned examples 1 have usually shown'one fixed filmover the integral coating of iron salt on the metal, I may use more thanone film to obtain further benefits from stepwise lubrication. Thus, thesurface of the steel to be worked may be treated with a solution suchfor'example as the baths of Example l containing .polythionate materialsequivalent to Wackenroders solution to form an integral adhered coatingto obtain iron sulfide upon the material. The thus treated metalafter'rinsin'g may be then filmed by contacting it with an alkalineearth polysulfide solution containing a colloidal carbohydrate such asstarch or polyvinyl alcohol and the like. After drying the latter filmon the metal it may be then quickly immersed in an aqueous soap andborax film such as previously described to provide a second film overthe previous polysulfide film. The material thus treated may then bedried and subjected to extreme cold work.

Although several embodiments of the invention have been herein shown anddescribed, it will be understood that in accordance with the provisionsof the patent statutes, numerous modifications of the construction shownmay be resorted to without departing from the spirit of this invention.

What I claim is: i

, 1. In the lubrication of a ferrous metal surface which is subjected tosliding friction, the steps which comprise forming on the surface anintegral coating by subjecting the surface to sulfur in the presence ofa reducing atmospher'e, and thereafter disposing over saidcoating anadherent meltable film deposited from solution and con taining a.m'eltable organic binder that is solid at room temperature, and a finelydivided inorganic solid compound insoluble in solutions of said binderand having a melting point below themelting point of iron and of theinorganic solids, at least one of which is an inorganic compound, whichsolids have a lower melting. point than the melting point of saidintegral coating, said organic binder also having a melting point lowerthan that of said integral coating and that of said finely dividedsolids, and thereafter subjecting the metal to deformation, whereby saidorganic binder both protects.

said integral coating and cooperates therewith and with said finelydivided solids to provide stepwise lubrication at different temperaturescaused by said deformation.

4. The process of working ferrous metal which comprises forming on thesurface of the metal a phosphate coating and superimposing thereon afixed film of a composition comprising a solid meltable organic bindingmaterial containing distributed therethrough a solid inorganic compoundmeltable at a temperature below the melting point of the ferrous metalphosphate of said coating and having a hardness not exceeding 5 on theMobs hardness scale, and thereafter deforming the metal.

5. A method of treating ferrous metal prior to deformation thereof bydrawing, which comprises subjecting said metal to contact with anaqueous solution comprising sulfur containing materials formed fromsodium tetrathionate in the presence of boric acid to form an integraladherent coating comprising ferrous sulfide on the metal, drying oversaid integral coating an aqueous liquid comprising an organic watersoluble film forming protective colloid and a meltable inorganiccompound to form a film that is solid at room temperature, which isdeposited from solution andwhich contains a meltaolej' solid organicbinder and a solid meltable inorganic compound having a scratch hardnessof less than 5 on the Mohs scale and a melting 'point less than themelting point of said integral coating and higher than the melting pointof said organic binder and thereafter deforming the metal.

6. In the lubrication of metals, the method of forming a lubricantcoating on ferrous metal surfaces by the steps which comprise subjectingthe metal to contact with an aqueous acidic coating and etching bathcontaining polythionates to form an integral adherent coating containingiron'sulfide upon the metal, the iron sulfide being derived fromreaction of the bath upon the ferrous surface, then rinsing the coatedmetal and then filming the integral surface coating and a scratchhardness less than integral coating of hexagonal black ferrous 'sulfideand superimposing on the thus coated metal a fluid composition capableof drying to a solid meltable film and comprising at least one rneltableand fusible solid inorganic compound distributed through a fluid vehiclecontaining an organic binding material, said inorganic compound beinginsoluble in said vehicle, being meltable at a temperature less than themelting point of the ferrous sulfide and having a Mohs hardness notexceeding 5, drying said fluid composition to a solid film and finallydeforming said metal.

3; In a process of deforming a ferrous metal surface, the steps whichcomprise forming on said surface an integral coating of a solid ferrouscompound having a melting point less than that of the ferrous metal andgreater than the temperatures at which hydrocarbon lubricating oils arestable and which has a scratch hardness of lessthan 5 on the MOMhardness scale, thereafter forming over said surface an adherent coatingcomprising an organic binder in a solid state but having a melting pointlower than that of said ferrous compound of said integral coating, and aplurality of finely divided coated metal with an alkaline earthpolysulfide solution containing a colloidal carbohydrate, drying thepolysul fide and colloid film and then applying an aqueous soap andborax lubricant filmovcr the previous polysulfide.

film and then drying the lubricant onto the coated metal surface.

7 .'ln a process of working ferrous metal, the steps which comprise (l)forming on the metal surface an integral iron salt that has a lowermelting point than the metal, (2) thereafter forming a meltablc fixedfilm vover said integral iron salt by coating the surface there of witha film-forming, liquid composition containing a water-soluble organicbinder that dries to a solid filrnand a meltable, solid inorganiccompound, said inorganic compound and organic binder having meltingpoints below that of the integral iron salt and having hardness lessthan 5 on the Mobs hardness scale and (3) thereafter working the metal,whereby said solid film both protects said iron salt and cooperatestherewith to provide, by difference in melting point, stepwiselubrication at the varying temperatures produced by the drawingoperation.

8. In a process of working ferrous metal, the steps which comprise (1)forming on the surface an integral iron salt that has a lower melting"point than the metal, (2) thereafter forming a meltable fixed film oversaid integral iron salt by coating the surface thereof with afilm-forming liquid composition containing a water-.

soluble organic binder that is solid at room temperature and a pluralityof solid meltable inorganic compounds distributed therethrough, saidinorganic compounds and meltable binder havingmelting points below thatof the integral iron salt,

integral iron salt and a scratch hardness less than onthe Mohs hardnessscale and the metal.

9. In a process of working ferrous metal, the steps which comprise (1)forming on the metal surface an integral iron. salt that has a lowermelting point than the metal. and a hardness less than 5 on Mohshardness scale, (ZJcoating the surface thereof with a film-formingaqueous solution containing a water-soluble organic binder and aplurality of water-soluble inorganic compounds which; remain distributedthrough the binder upon drying, said binder and inorganic compoundshaving melting points below the melting point of the integral iron saltand a scratch hardness less than 5 on Mohs' hardness scale, (3) dryingsaid solution to form a solid-at-room-temperature, meltable, fixed filmover said and (4) thereafter working the metal.

10. A method of treating ferrous metal which comprises subjecting saidmetal to contact with an acidic aqueous solution containing (1)colloidal sulfur, sulfur dioxide, and a mixture of polythionic acids,(2) a water-soluble protective colloid, (3) a water-soluble,

(3) thereafter working lubricatingorganic binder, and(4) a member of thegroup consisting of fusible borates and phosphates, so that an integralcoating is formed on the metal while in solution, then with-drawing themetal from said solution .so as to leave an overlying film of organicbinder with fusible borates and phosphates therein drying said film onthe'ferrous metal, and thereafter deforming said metal with the aidof adie.

11. The method of claim 7 in which the integral coating comprises aniron sulfide.

12. The method of claim 7 in which the integral coating comprises aniron phosphate.

'13. The method of claim 9, in which the integral iron salt is waterinsoluble.

' 14. A both for coating ferrous metal in preparation to.

a deforming action, comprising an acidic aqueous solution including awater-soluble protective colloid; a water-soluble stearate; a compound,the composiiion of which includes a radical selected from the groupconsisting of acidic phosphate radicals and acidic boratcrcdicals; and acompound selected from the group consisting of sodium thiosulfate andthe sulfur decomposition products of sodium thiosulfaie.'

15. A method of treating a ferrous metal having an iniegraI-coailngselected from the group consisting of iron sulfide coatings, phosphatecoatings, and precipitated coatings of organic acid salts, providedthereon, comprising the step of superimposing a second coating over saidintegrol coating; said second coating comprising an adherent m'eltablefilm containing a meltable organic binder that is solid at roomtemperature and an inorganic solid compound that is insoluble insolutions of said binder and having a melting point below the meltingpoint of iron, and a scratch hardness less than 5 on a Mohs" scale.

16. As a new article of manufacture, a deformable ferrous metal,comprising, a ferrous metal base; coating selected'from the groupconsisting of iron sulfide coatings, phosphate coatings und precipitatedcoatings of organicacid salts, bonded to said ferrous metal base; and anadherent meliuble film superimposed on sold an integral,

integral coating; and meliable pigments dispersed in said adherentmeliable film; said pigments having a melting point below the meltingpoint ofsaid integral coatings,

and a scratch hardness less than 5 on a Mohs' scale.

17. A coating bath useablc to provide an integral iron sulfide coatingon a ferrous metal, comprising; an admixture of an aqueous, acidulatedsolution, including an unstable inorganic sulfur compound selected fromthe group consisting of sodium thiosulfaie, sodium polythionaie andsulfur mono-chloride with a water-soluble stearatc.

18.. A coating bath useable to provide on integral iron sulfidecoatingon a ferrous metal, ous, acidulated solution including a water-solublesicaruie.

' 19. As a new article of manufacture, d piece of blank metal stock forsubsequent forming operations; sold stock being coated with an integralphosphate coating; said integral phosphate coating being covered with ansodium th iosulfatc and adherent meliable film superimposed thereon;said adherent meliable therein; melting point of said integral coatingsscratch hardness less than 5 Mohs' scale.

20. As a new article of manufacture, a piece of blank film havingmeltable pigments dispersed metal stock for subsequent formingoperations; said stock being coated with an integral oxalate coating;said integral oxalate coating being covered with an adherent meltablefilm superimposed thereon; said adherent meliable film having melnzblepigments dispersed therein; said pigmerits having a melting point belowthe melting point of said integral coatings and having a scratchhardness less 5 on aMohs scale. v

21. As a new article of manufacture, a piece of blank metal stock forsubsequent forming operations; said stock being coated with an integralcoating of a salt of an organic acid; said coating being covered with anadherent meltable film superimposed thereon; said adherent meltable filmhaving meltable pigments dispersed therein; said pigments having amelting point below of said integral coatings and having a scratchhardness less than 5 on a Mobs scale.

References Cited in the-file of this patent or the originalpatent OTHERREFERENCES lished 1943, 4th edition.

Ephraim: "Inorganic Chemistry," pages 5554557, pubcomprising: an aque-.

said pigments having a melting point below. the. and having. a

the melting point l

